Translated from "Ovchinnikov bulletin of biotechnology and physical and chemical biology" V.8, No 1, pp 16-26, 2012
We have discovered and purified a new methyl-directed site-specific DNA endonuclease MteI from bacterial strain Microbacterium testaceum 17B. The enzyme recognizes methylated DNA sequence and doesn’t cleave unmethylated DNA. MteI is a first methyl-directed site-specific DNA endonuclease recognizing a prolonged DNA sequence and its activity depends on a number of 5-methycytosines and their positions in the recognition site. MteI cleaves DNA sequence 5’-G(5mC)G(5mC)↑NG(5mC)GC-3’/3’-CG(5mC)GN↓(5mC)G(5mC)G-5’ as indicated by arrows and this nonanucleotide is a minimal recognition site. The enzyme activity is significantly higher if 5’-GC-3’ dinucleotides in this site are replaced by 5’-G(5mC)-3’ dinucleotides and additional 5’-G(5mC)-3’ dinucleotides are present at 5’-ends in both DNA strands. Due to an ability to cleave only prolonged methylated DNA sequences MteI may find a practical application in the molecular biology and epigenetics studies.
Translated from "Ovchinnikov bulletin of biotechnology and physical and chemical biology" V.7, No 3, pp 35-42, 2011
We have discovered and purified a new methyl-directed site-specific DNA endonuclease PkrI from bacterial strain Planomicrobium koreense 78k. PkrI recognizes and cuts methylated DNA sequence 5'-GCNGC-3'/3'-CGNCG-5' carrying at least three 5-methylcytosimes and doesn’t cleave unmethylated DNA. Due to its ability to cleave only modified DNA PkrI may find a practical application in genetic engineering experiments as well as in determination of DNA methylation status.